Spinach from Ibaraki Prefecture is left unsold at the Metropolitan Central Wholesale Market in Tokyo Tuesday. The Japanese government halted shipments of spinach from Ibaraki Prefecture, one of the areas where spinach was found to be tainted with radioactive iodine.

Washington — Japanese authorities say they have found radiation-tainted spinach and raw milk near the Fukushima nuclear plant. As a result they have banned the sale of leafy vegetables and milk from the surrounding countryside. That sounds like a serious situation. Is there any chance that foodstuffs in America will be tainted by radioactivity?

No, they probably will not. Any plume of radioactivity from the devastated plant would be so diluted by the time it reaches the United States that it would have no discernable effect on West Coast vegetables. Wind and rain would essentially mix any such emissions into the vast volume of the atmosphere of the Northern Hemisphere, according to Tom McKone, a senior staff scientist and health-risk exposure expert at the Lawrence Berkeley National Laboratory.

Plus, there is little chance radioactive food from Japan will end up in US stores. Japanese food imports account for only four percent of total US food imports, according to the US Food and Drug Administration. The FDA’s import tracking system has been set to automatically flag shipments of regulated Japanese consumables.

That is a layer on top of the Japanese precautions. Japan itself has now ordered a stop to sales of raw milk from Fukushima prefecture following the discovery of elevated levels of iodine-131 in milk samples. The sale of leafy vegetables – which have ample surface area to absorb radioactive contamination – from Fukushima and three surrounding prefectures is also banned.

“Based on current information, there is no risk to the US food supply,” said the FDA in a statement.

The radioactivity detected in Japanese milk and greens is quite low-level. You would have to eat about two pounds of contaminated spinach to absorb the same amount of radiation you would get from a CT scan of your head.

But Japanese authorities are trying to act upon one of the lessons of the Chernobyl nuclear disaster. After Chernobyl, Soviet officials did not stop the surrounding population from eating vegetables grown locally and drinking milk from cows that munched on local grass. They did not understand that this was a pathway for radioactive iodine to concentrate and collect in people’s thyroid glands.

Children and adolescents were particularly affected by the tainted milk. In the years since the 1986 Chernobyl disaster there has been a large increase in the rate of thyroid cancers among those who were young at the time and lived near the reactor, according to academic follow-up studies.

The good news is that survival rates for thyroid cancer patients are around 95 percent. Furthermore, scientists have detected no increase in that disease among Chernobyl-area residents who are were already adults at the time of the meltdown. Nor have they detected any radiation-linked increase in other types of cancer among the local Chernobyl population – though evidence of such an increase might be difficult to detect.

This bears on the health risks now faced by the Japanese who live near Fukushima, according to Dr. McKone of the Lawrence Berkeley National Laboratory.

“The risks for the Japanese will vary with their distance from the plant, and based on our experiences from Chernobyl, will be much lower than what people now fear,” he writes.